Capacitors are indispensable parts for various electronic systems, which are widely used for signal filtering and decoupling, energy transfer and storage, and charge/information retention. Integration of capacitors with high capacitance density and low resistance are leverage in many applications.
For instance, integrated capacitors can be use for power converters, especially power converters with small sizes (e.g. for portable and wearable electronics, fully integrated power supply on-chip (PwrSoC) applications, point-of-load (POL) applications, and granularity power supply applications). Power converters use capacitors to store or release energy at different intervals for a smooth and stable output voltage. For example, in linear voltage regulators or inductive switched-mode power converters, capacitors are connected in parallel with the load to absorb the excessive energy when the output voltage increases and releases the stored energy when the output voltage drops. In switched capacitor power converters, capacitors are used as medium to transfer energy from the input to the load by charging and discharging. In both cases, there will be a ripple current flowing through the capacitor. As a result, integrated capacitors with low resistance are important for achieving high-efficiency power converters.
Another application that leverages capacitors with low resistance are microwaves. In order to achieve a smaller signal distortion, lower loss, and create less heat dissipation in a microwave system, high quality factor (Q) capacitors can be used. The Q factor of a capacitor is defined as the ratio of its reactance to its resistance. Therefore, in order to build integrated microwave systems, integrated capacitors with lower resistance can be leveraged to increase the Q factor.
This background relating to fabrication of integrated capacitors is merely intended to provide a contextual overview of some current capacitor fabrication technology, and is not intended to be exhaustive. Other context regarding current state may become apparent upon review of the following detailed description.